all mahabodhisattvas can appear in different forms according to
ppl's capacities and needs. e.g guan yin appears as male form in
tibet but female form in china.
wen shu guang fa tian zun havent heard before 
I always wanted to ask this qn.
Issit only the Buddhas have attained nirvana? Even Dizhang Wang not
attained nirvana right?
The part from chinese mythology about gu3 fo2 true or not? Like got
one ran2 deng1 gu3 fo2 .. true or not? I know mi2 le4 fo4 must be
true lah, just that he is future Buddha?
The Theravadins believe Shakyamuni Buddha entered into
Parinirvana, the Mahayana believes Shakyamuni Buddha manifest
Nirvana only as expedient means but ultimately is still teaching in
the 3000 world system. Ancient Buddha is not a mythology but part
of the Mahayana teachings.